Modified osteotome sinus floor elevation using combination platelet rich fibrin, bone graft materials, and immediate implant placement in the posterior maxilla.

The osteotome technique is more predictable with simultaneous implant placement when there is <5-7 mm of preexisting alveolar bone height beneath sinus. Proper combination of platelet rich fibrin, mineralized freeze-dried human bone allograft, and autogenous bone has been recommended for this situation. The purpose of this article was to describe the proper method and materials which can grow >10 mm bone with osteotome technique and grafting materials where the edentulous posterior maxilla radio-graphically showed less bone between the alveolar crest and sinus floor.

INTRODUCTION

Implant placement in posterior maxillary jaw is more complicated because of lack available bone compared to mandible jaw bone. Success of implant in the posterior maxillary bone is complex because of type III and IV bone.[123] After the extraction of the tooth residual ridge resorption occur in buccolingual and occlusoapial direction. There is a significant decrease in the height of the bone available in the posterior section of the upper arcade. Consequently, we often end up with a residual bone height of <3-5 mm between the alveolar ridge of the crest and the sinus floor.[45] It is difficult to place >11 mm of implant in 2-3 mm bone without sinus lift in posterior maxillary bone.[67] As such this area requires bone augmentation beneath sinus to increase vertical height of bone. There are currently two principle techniques of penetrating crestal bone and in order to elevate maxillary sinus depending upon the availability of bone height.[67] The first technique is open or lateral window technique. Second includes close window technique. The close window technique use variety of tools and materials such as bone grafts, sinus elevators, balloon, sinus condenser, sinus curettes, and collagen to lift the sinus. Nevertheless, each technique shows advantages and disadvantages. Lateral access window shows a more consolidation outcome in literature; however, it is very traumatic and complex technique to perform. The osteotome sinus floor elevation (OSFE) procedure, introduced by summers may be less invasive, less time-consuming, cost-effective, and reduces postoperative discomfort to the patient. The procedure consists of elevating the Schneiderian membrane with osteotomes through a crestal approach, placing simultaneously platelet-rich fibrin (PRF), mineralized freeze-dried human bone allograft (MFDBA), autogenous bone and the implant at the osteotomy site.[891011] These PRF and bone grafts are thought to provide a cushion during membrane elevation and reduce sinus perforation. The use of PRF and bone graft material during simultaneous sinus lift helps to promote natural bone regeneration.[1213] The key point of this new method is to maintain the Schneiderian membrane in the highest possible position, increasing simultaneous thin residual bone height >9-10 mm and width 1-2 mm.[13] Although summers did not define a minimum presurgical residual bone height in the original article,[8] other author have made recommendations ranging from 7-9 to 6 mm.[1415] The aim of this case report was to evaluate a modified OSFE technique for increased posterior maxillary bone height and width using PRF that is rich in growth factor, autogenous bone that is full of live endosteal osteoblast cells and MBDBA that has osteoinductive property.[9101112]

CASE REPORT

A 67-year-old female patient reported to the Department of Periodontology and Oral Implantology with the chief complaint of having missing teeth in right and left side of the posterior maxilla. There was no significant medical history. On enquiring about previous dental treatment, it was found out that the tooth was lost because of caries and periodontal disease. Preoperative computerized tomography (CT) scans were performed to obtain an accurate measurement of the bone before surgery. Immediate and 8 months postoperative CT scans were performed to check the proper placement and success rate of the implants, bone formation, and sinus membrane position. Patient had maxillary posterior bone - 1.49 mm on the right side and 1.47 mm on the left side between the alveolar crest and maxillary sinus as seen in Figure 1a.

Figure 1

Preoperative computerized tomography (CT) scan was taken and postoperative CT after 8 months of implant placement. (a) Bone height present is 1.49 mm between membrane and ridge preoperatively (b) Bone height presents 15.43 mm between membrane and ridge after 8 months of implant placement Preoperative and postoperative computerized tomography

Presurgical preparation included medical, dental, and computerized axial tomography (CAT) scan radiographic evaluations and basic dental therapy to alleviate preexisting medical-dental problems. Prior to implant surgery, informed consent for bone graft and sinus lifting of the implant, CAT scan consent was obtained from the patient. Patient received 625 mg augmentin (amoxicillin and clavulanate potassium) twice in a day before surgery. The patient was treated under oral sedation or intravenous sedations. Patient was treated with 5 mg of triazolam orally and then draped with sterile surgical barrier. Before a surgical procedure start, a full mouth prophylaxis was done on surgery patient. The posterior quadrant of the maxilla was anesthetized via local anesthesia injection 2% lidocaine HCL and epinephrine 1:100,000 in a 30-gauge needle. A direct, full thickness midcrestal incision with a #15 blade was made through the mucoperiosteum to the crest of the ridge. Full thickness reflection of buccal and palatal tissues exposed the alveolar ridge. To reflect the flap, molt elevator was used. The implant position was marked on the alveolar crest with a small trephine drill (Ø 2.0 mm). After locating the implant position, the preparation was widened with two sizes internally irrigated trephine (Ø 3.5 mm and Ø 4.25 mm) drill. Minimal pilot drilling (Ø 2.0 mm) was performed to a depth approximately 1 mm away from the sinus floor boundary. The osteotomy site was gently tapped with mallet and osteotome number three or four. Intra oral radiograph of the osteotomy site was taken to determine the position of the sinus membrane as seen in Figure 2a.

Figure 2

(a) Preoperative radiograph before implant placement (b) Bone grafting during surgery with an osteotome technique (c) Eight months after implant placement

At the same time, a 4-5 vials of blood was collected from the patient's vein, and blood is spun by a special machine called a centrifuge and spun for approximately 12 min. The PRF obtained is mixed with bone graft material. Pieces of PRF are made with scissor. The drops of clindamycin and cefazolin are added into the pieces of the PRF clot. These small pieces of the membrane are placed inside the osteotomy socket as a cushion during sinus lifting. A mixture of the MFDBA were taken in the separate container saturated it with saline. After 10 min, the excess fluid was drained, and clindamycin and cefazolin powder added into it. The bone particles and pieces of membrane were placed inside the osteotomy site. The osteotomy site with membrane and bone was gently tapped with osteotomes and mallet. Autogenous bone grafts from maxillary tuberosity area or bone removed during the site preparation from trephine were used to fill out the osteotomy site. The membrane and bone particles protect sinus membrane from perforation. Osteotome site was packed with bone and membrane after gradually adding bone particles and tapping it with osteotome and mallet. Bleeding from the osteotome site provides sign regarding the perforation of the sinus membrane. If bleeding does not occur from the site, it shows that perforation happened in the sinus membrane. Trial implant is placed inside the osteotome site to check adequate width of osteotome site. After checking with trial implant, actual size implant was placed in the osteotomy site. All the implants achieved primary stability. Ten to twelve small holes were made with surgical quarter round bur on the buccal surface of the posterior maxilla to initiate fast healing at the implant site. Bone from the maxillary tuberosity is taken and crushed with a bone crusher forceps. Crushed bone pieces and the rest of MFDBA particles are placed around the implant mainly on the buccal surface. Implant is covered with healing collar or cover screw. Placement of healing collar or cover screw is dependent upon occlusal clearance. Occlusal clearance between maxillary ridge bone and mandibular teeth is <5 mm than cover screws are placed on the implant. PRF is placed in around healing collar for excellent healing of soft tissues. After repositioning the soft tissues, primary closure was attained using 4-0 chromic gut suture. The site was allowed to heal for 3 months. After 4 months, abutments were placed on the implants and restorative procedure was initiated.

RESULT

Patient completed the scheduled follow-up visits up to the 8 months. No implant failure was recorded during the follow-ups. No pathologic conditions in the implants site were seen on radiographic follow-ups after 8 months as seen in Figure 2c. After 8 months, implants were clinically and radiographically stable. In general, good function of implants and restorations were achieved. Implants were stable at the time of abutment connection which was performed after a healing period of 3-4 months. Patient reported full satisfaction for function, phonetics, and esthetics.

At the osteotomy site, combination use of PRF and bone grafts, it served as a cushion below the maxillary sinus floor, reducing the risk of perforation of the sinus membrane. The elevation of the sinus membrane was one of the most delicate parts of the technique, and it was performed using osteotomes, with the PRF and bone graft itself.

Computerized tomography scan results

The CT scan carried out 8 months postinsertion showed a dense mineralized bone surrounding the implants. In the case, it was difficult to delineate the border line between sinus floor and newly formed tissue. The original bone height below the sinus floor as measured on the preoperative CT scan was 1.47 and 1.49 mm at two sites and on second CT scan evaluation after 8 months postsurgery, the bone height achieved was of 15.42 mm and 16.94 respectively [Figures 1–4].

Figure 4

(a) Preoperative computerized tomography scan showing top view of the sinus membrane (b) Postoperative computerized tomography scan after 8 months of implant placement showing sinus floor elevation without perforation and bone formation Radiographic assessment of bone levels before and after implant placement between sinus membrane and ridge

(a) Cross-sectional view of the site of the right molar showing approximately <2 mm bone height (b) Cross-sectional view of the site of the right molar after 8 months showing approximately >15 mm bone height

DISCUSSION

Summer's osteotomes modified techniques may allow performing a safe and effective osteotome-related sinus membrane elevation with simultaneous implant placement in posterior maxillary area, thereby drastically reducing the total treatment time, expense and also improve healing time.[89] Sinus membrane perforations using a conventional osteotomy were reported in studies by Toffler[16] and Ferrigno et al.,[17] with percentage of 4.7% and 2.2% respectively. The proposal for using a material to weaken the impact of the sinus membrane from perforations was suggested by Lazara et al.;(1998) however, the type of material was not specified. Therefore, in the present clinical case the choice was to use PRF and bone graft materials, mainly because its biocompatibility, resilience, and availability. The meta-analysis conducted by Tong et al. on bone added OSFE reported on implant survival for 18 months or more. The survival rate was 90% when autogenous bone alone was used, and the survival rate was 87%. When freeze-dried demineralized bone (FDDB) bone alone was used. The survival 98% when FDDB bone and autogenous bone were both used together. Based on data, the authors suggested implant survival rates can increase if the combinations of materials are used in an appropriate way.[18] This method has proven to be highly predictable to gain >10 mm bone height in posterior maxillary area. No complications have occurred in the patient treated thus far, and no implant failures have occurred. Compare with other technique, which requires minimum 6-9 months of healing, this technique typically need only 3-4 months of healing. One reason could be smaller hole is made for access in the sinus cavity. This technique rarely compromises blood supply. Main advantage of this technique is that implant and osteotomy site gets blood supply from buccal, lingual, mesial, and distal surfaces of blood vessels while in lateral window technique implant and bone grafts gets its blood supply largely from buccal surfaces of blood vessels. In lateral window approach risks, the possibility of breaching the blood supply, since arteries supplying the area are situated very close to mucoperiosteal region of the potential window site.[1415] Second reason could be PRF, which promotes bone regeneration and soft tissue healing, improving bonding between bone and implant surface. It also serves as protection barrier to the sinus membrane, it is much less expensive than commercial membrane. PRF may allow gentle elevation of membrane, and represent an excellent source of growth factors.[1213] The platelets and the growth factors included in the fluid released by membrane may locally enhance bone regeneration as they come in contact with Schneiderian membrane. It also has consistent regenerative power as it combine with osteoprogenitor cells from MFDBA and autogenous bone.[192021] Third reason could be autogenous bone graft from maxillary tuberosity area which has an osteogenic potential related to the number of surviving osteoblasts and potential osteoinductive effect brought about by the release of bone morphogenic proteins and other growth factors and it also accelerates the bone production sequence.[2223] Fourth reason could be MFDBA, which gives the signal from their proteins to neighboring mesenchymal cells and differentiate them into bone producing cells.[242526]

Several studies have demonstrated that the failure rate is higher when the bone crest is inferior to 5 mm.[16] Nevertheless, according to Li,[27] the osteotomy technique can be used even in residual ridges with heights of 3-4 mm, if primary stability has been achieved. In the present clinical case, the height of remaining bone was 1-2 mm, implant success rate was higher. Further investigation is needed to establish the actual contribution of PRF, bone graft materials at osteotomy site to the positive outcome obtained with this modified technique, and to determine whether less residual bone height in maxilla can be successfully achieved with this modified technique.

CONCLUSION

The use of PRF, MFDBA, and autogenous bone during OSFE technique and implantation is a secure and reliable option. This autologous and inexpensive material can be considered as appropriate materials for adequate natural bone regeneration and soft tissue healing. However, in this technique the alveolar bone ridge height and Its width Is of prime importance and considerations. The use of PRF during a sinus lift, with a combination of MFDBA and autogenous bone, may be beneficial, particularly for the posterior maxillary bone growth. This modified method reduced total treatment time, expense of the patients and should be analyzed in further studies.